Excess deaths during the August 2003 heat wave in Paris, France

During the August 2003 heat wave in France, almost 15,000 excess deaths were recorded. Paris was severely affected, with an excess death rate of 141%. This study had two aims: to identify individual factors associated with excess deaths during a heat wave in an urban environment and to describe the spatial distribution of deaths within the French capital.

The study population included all people who died at home between August 1st and 20th, 2003 (N=961). We identified factors associated with excess deaths by comparing the sociodemographic characteristics of the study population with those of people who died at home during the same period in reference years (2000, 2001, 2002) (N=530). Spatial differences were analysed by calculating comparative mortality rates within Paris during August 2003. Mortality ratio was determined to demonstrate temporal variations in mortality between the heat wave period and reference years.

The major factors associated with excess death were: age over 75 years (adjusted OR=1.44 (1.10-1.90), being female (adjusted OR=1.43 (1.11-1.83)), not being married (adjusted OR=1.63 (1.23-2.15)), particularly for men. Being a foreigner appeared to be a protective factor for women. Comparative mortality rates by neighbourhood showed a gradient in excess deaths from North-West to South-East. The mortality ratio was 5.44 (5.10-5.79), with very high rates of excess death in the South (12th, 13th, 14th and 15th "arrondissement").

The August 2003 heat wave in Paris was associated with both an exceptional increase in mortality rates and changes in the characteristics of those dying and spatial distribution of mortality. Understanding the effects of a heat wave on mortality can probably be improved by an analysis of risk at two levels: individual and contextual.